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Criminal | Defences

Automatism: Criteria

Revision Note | A Level

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  • automatism can be a defence in relation to all offences
  • two elements required: act is involuntary and caused by an external factor
  • if D successfully argues automatism he is found not liable and acquitted

Involuntary act

  • D must have acted involuntarily
  • involuntary defined as mind not controlling limbs in a purposeful way

    Bratty (1963)

    • D strangled V in his car
    • evidence showed D suffered a psychomotor epileptic seizure at time of the killing, D claimed that.. a blackness came over him..
    • Lord Denning: ..No act is punishable if it is done involuntarily: and an involuntary act in this context… means an act which is done by the muscles without any control by the mind such as a spasm, a reflex action or a convulsion; or an act done by a person who is not conscious of what he is doing such as an act done whilst suffering from concussion or whilst sleepwalking…
  • partial control can undermine automatism defence

    Attorney General’s Reference (No. 2 of 1992)

    • D, an HGV driver, killed Vs, when he drove on to motorway hard shoulder
    • D’s defence was driving without awareness, a trance like state induced by repetitive stimuli experienced on long journeys
    • trial judge left defence of automatism available to jury, D acquitted
    • on appeal decided as a matter of law if D is partly in control automatism could not be considered

External factor

  • must be caused by an external factor not internal (such as disease)

    Quick (1973)

    • D, a nurse, assaulted V, a paraplegic patient, V sustained injuries including black eyes, broken nose and bruising, evidence confirmed injuries could not be self inflicted
    • D was a diabetic, he had taken his insulin but not eaten enough, D suffering from hypoglycaemia, caused by too much insulin and leads to mental instability
    • Court of Appeal found hypoglycaemia did not come within definition of insanity as caused by drug insulin, D could rely on automatism and was entitled to be acquitted
  • general principle that internal factors lead to insanity and external factors to automatism

    Hennessey (1989)

    • D was driving a stolen car while disqualified
    • D, was diabetic and not taken his insulin for four days, D argued he was suffering from hyperglycaemia, which can lead to unconscious actions
    • court found hyperglycaemia was caused by an internal factor, diabetes, so automatism not available (but insanity was)
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